1. Technical Field
Devices consistent with the present invention relate to a component built-in wiring board which includes a capacitor having an electrode layer and a dielectric layer.
2. Related Art
In recent years, a semiconductor integrated circuit device (an IC chip) to be used as a microprocessor of a computer has been enhanced in a speed and a function increasingly. Incidentally, there is a tendency that the number of terminals is increased and a pitch between the terminals is also reduced. In general, a large number of terminals are densely disposed in an array on a bottom surface of the IC chip, and the terminal group is connected to a terminal group on a mother board side by flip chip bonding. The pitch between the terminals has a great difference for the terminal group on the IC chip side and the terminal group on the mother board side. For this reason, it is hard to directly connect the IC chip onto the mother board. Therefore, there is usually employed a technique for fabricating a package including an IC chip in a core substrate of a wiring board (see e.g., JP-A-2003-309243 (e.g., FIG. 1), JP-A-2002-246761 (e.g., FIG. 14)) or a package having an IC chip mounted on a wiring board, and mounting the package on a mother board. In a wiring board constituting the package of this type, it has been proposed to provide a capacitor (or condenser) in order to reduce a switching noise and to stabilize a power voltage in the IC chip. As an example, there has been provided a wiring board in which a chip-shaped capacitor is embedded in a core substrate and a build-up layer is formed on a front surface and a back surface of the core substrate.
In the case, although a component such as an IC chip is included in a core substrate, a space in the core substrate is occupied by the IC chip. Therefore, it is hard to embed a capacitor in the core substrate. For this reason, the capacitor is to be mounted on a wiring board. Even if the capacitor can be embedded in the core substrate, moreover, it is necessary to dispose the capacitor to keep away from the IC chip. As a result, a length of a wiring for connecting the capacitor to the IC chip is likely to be increased. Therefore, an inductance component of the wiring is likely to be increased. Consequently, it is impossible to reliably reduce a switching noise of the IC chip by the capacitor and to surely stabilize a power voltage.